1. Field
The present invention relates generally to an operational amplifier (“op-amp”) and more particularly to an op-amp capable of self-biasing its input voltage(s), and a method for self-biasing said input voltage(s). Said op-amp may also include a transimpedance input stage.
2. Description of Related Art
Conventional op-amps are often hampered by low gains when high gains are required or instability at high gains at high frequencies. Moreover, construction of conventional op-amps may also require complementary technology for implementation which can limit the material used for the fabrication of op-amps.
Furthermore, conventional op-amps often require a separate, external biasing sequence and a separate, external voltage source to safely bias the input voltage(s) of an op-amp. Biasing is critical to an op-amp as it allows for the gradual modification of the op-amp's input voltage(s) to its design value(s), as opposed to a sudden, excessive modification to its design value(s). A sudden, excessive modification of an op-amp's input voltage(s) renders other amplifier stages in the op-amp highly susceptible to destruction. Hence, a key feature of biasing is to prevent the other amplifier stages from destruction by way of a gradual modification of the op-amp's input voltage(s). Therefore, this invention is advantageous for real-world applications because it allows an op-amp, with no connection to any separate, external biasing sequence and any separate, external voltage source, to be rapidly turned on and off without risk of destruction to other amplifier stages. Moreover, the performance of such op-amps remains strong, as there is no change to the op-amp RF performance in terms of bandwidth and linearity. This invention is particularly advantageous to op-amps using feedback or op-amps where no DC voltage source is available to the RF input port(s).
Thus, there is a need for an op-amp capable of (a) self-biasing its input voltage(s), (b) function stably with higher gains at high frequencies, and (c) which can operate without complementary technology. Moreover, there is a need for a method for allowing for such an op-amp to self-bias its input voltage(s) without a separate, external biasing sequence and a separate, external voltage source.